Interpretive Summary: Sugarcane is the primary crop in the Everglades Agricultural Area in Florida. Sugarcane growers often must make water-management decisions that consider both the yield of their crop and environmental concerns. An experiment conducted in the plant-cane and first-ratoon crops of sugarcane grown in pots studied the effects on yields on two cultivars of 3-week floods applied 46 days prior to harvest. Theoretical recoverable sugar of one cultivar was improved by September, October, and November floods and reduced by January floods. Theoretical recoverable sugar of the second cultivar was not affected by floods. Cane yields and sugar production were not affected by floods in the plant-cane crop or by September, October, or February floods of the first-ratoon crop. Cane yields and sugar production were reduced in the first-ratoon crop by the November, December, and January floods. These floods would have related economic benefits, but probably not of sufficient magnitude to compensate for yield losses. Benefits include fewer soil fires after preharvest burns, possible improved emergence of successively planted sugarcane fields, and the ability to flood other fields as a means of freeze protection. Growers are already imposing floods of less than 1-day duration to obtain the first two of these benefits. Also identified was the possibility of using these 21-day floods to help resolve public water storage issues in south Florida. Cost-benefit analyses would be needed to determine if the water-storage benefits would be of sufficient value to public water managers to offset the increased flood-related costs to sugarcane growers. Identification of agronomic practices tolerant to periodic floods will help sustain sugarcane production in Florida and enable farmers in the Everglades Agricultural Area to better adapt to and support hydrologic changes related to Everglades restoration.

Technical Abstract:
Some Florida sugarcane (Saccharum spp.) growers apply short-duration (less than 1-d) floods prior to harvest to prevent fires that form sporadically on their organic soils after preharvest burns. Extending these floods in duration may reduce yields but also provide options to manage on-farm floods for freeze protection and provide water-management options with beneficial environmental impacts. The purpose of this study was to compare the effects of continuous drainage with 21-d floods, initiated 46 d prior to harvest, on sugar and cane yields of two sugarcane cultivars. During the plant-cane and first-ratoon crops, pots of cultivars CP 72-2086 and CP 80-1827 at Canal Point, FL, were continuously drained or treated with 21-d floods in monthly intervals from September through February. Each pot was flooded only once per crop year, so month of flood was a distinct, not a repeated, treatment. Yields of theoretical recoverable sucrose (TRS) measured as kg sucrose t-1 cane, increased for CP 80-1827 after September and October floods of the plant-cane crop but decreased after the January flood. Conversely, floods in October reduced TRS in the plant-cane crop for CP 72-2086. In the first-ratoon crop, flooding did not affect the TRS of either cultivar. Cane yields and sugar production, both measured as kg m-2, were reduced by flooding in the first-ratoon crops following the November, December, and January floods. Further research is needed to quantify flood durations that would not result in yield losses and to conduct cost-benefit analyses that include agronomic and environmental benefits of preharvest flooding.